1. Field of the Invention
The present invention relates to a tool capable of moving two mechanical pieces away from each other. More specifically, the invention is concerned with a tool of the type comprising first and second, pivotally interconnected arms each comprising a notched free end for engaging an edge of a respective mechanical piece.
2. Brief Description of the Prior Art
U.S. Pat. No. 4,768,408 granted to the Applicant on Sep. 6, 1988, describes a tool of the above type capable of moving the semicircular shoes of a drum brake away from each other in order to release the automatically adjustable spacer. As well known in the art, this spacer is mounted between two adjacent ends of the semicircular brake shoes and its length is automatically increased as the brake linings of the shoes wear in order to maintain a determined spacing between the linings and the inner cylindrical surface of the drum when no braking operation is performed. Usually, the spacer is lengthened by means of a well known mechanism in response to too ample a movement of the brake shoes upon breaking. This prevents reduction of the braking performances as the brake linings wear, caused by excessive longitudinal movement of the pistons of the wheel cylinder.
At the level of the spacer, the brake shoes are biased toward each other by at least one helicoidal spring, whereby this spacer is squeezed between the shoes. In order to release the spacer for maintenance or repair purposes, the brake shoes must be moved away from each other against the biasing force produced by the spring. A tool is usually required to carry out this task.
The tool of U.S. Pat. No. 4,768,408 has been designed to carry out this operation. It comprises a first arm having an handgrip portion and an arcuate arm portion formed with a notched free end. It also comprises a second arm with a notched free end and with a proximate end pivotally connected to the arcuate portion of the first arm. The drum brake shoes comprise generally facing transversal edges capable of being engaged by the notched free ends of the first and second arms. When the notches of the first and second arms are engaged with the generally facing edges of the brake shoes, the handgrip portion can be pushed toward the second arm to move the brake shoes away from each other and release the spacer to remove, adjust or install it.
As the notches of the prior art tool are oriented in the direction of the longitudinal axes of the arms, the portion of the first arm between the handgrip portion and its notched end must be arcuate in order to enable full engagement of the notches with the generally facing edges before operating the tool to move the brake shoes away from each other.
The tool of U.S. Pat. No. 4,768,408 therefore presents the drawback of comprising an arcuate arm portion. This is susceptible to complicate manufacture of the tool and to increase its cost on the market when certain techniques of production are used, for example when the arcuate arm portion is obtained by curving a bar of steel. Also, the curvature in the arcuate arm portion complicates the conception of any mechanism capable of adjusting the position of the pivotal connection along at least one of the arms in function of the distance separating the generally facing edges of the brake shoes. The arcuate arm portion further increases the tool's bulkiness; storage of the tool accordingly requires additional space in the toolbox. Moreover, when a die is used to manufacture the tool, the larger overall dimensions of the arm including the arcuate portion increase the cost of the die.